Garage floor pitch problem

[jbs]

I am building a new 32x40 garage (see here), and, I have a bit of a problem with the concrete at the overhead doors. The pitch is not sufficient for drainage, and there is a very slight low spot 8-30 inches inside the door, so when it rains I get puddles just inside the doors (when they are closed).

The overall ("macro") pitch is good. It is nearly flat for the back 20', then pitched about 4-5" over the next 20'. It is just right at the door opening that there is a slight lip or uptick that extends outside the door the 8 or so inches to the edge of the slab.

The contractor is willing to try and work with me to fix it. He was going to grind it down, but seeing how much it would need (1/8"-1/4" over both 10' wide openings), he suggested a threshold. While this might help, I am concerned that it would never seal well enough to keep water out. I told him he could try it on one door and if it didn't work we could look for a plan B. Is it reasonable to think a big concrete grinder could work in this situation? What would you suggest?

 

[tc2000]

I would search the forum, I had a similar problem with my previous slap and I found a couple threads with good ideas. One idea was to grind channels towards the door with the right pitch (assuming your apron wasn't in the way. Good luck.

 

[folgers]

What your contractor should have done was put a 3/4 inch slope on the 8" of concrete that extends beyond the overhead door. Without that slope wind driven rain will puddle up against the door and run inside. I think you need to take off more than 1/8" or a 1/4" inch to keep the rain out. If you have an approach poured make sure it sits well below the front edge of the floor slab.
I haven't ground concrete before but I think with the right grinder your doors could be fixed, but the ground concrete won't look the same as the finished concrete in the rest of your garage.

 

[jbs]

Good advice (especially the search, I always do that first but spaced b/c I started the post as an update to my build thread, not a new thread with a question). I think I'll have him try the concrete saw to put some drain channels in and then add the threshold. Thanks

 

[darkk]

You can also install a metal weather strip/bump. My older garage has a thick metal ridge like a 1/3rd round pipe across the opening to both side lips. It keeps anything from seeping in. It is about 1" high.

 

[BobbyK]

It seems this is an actual "working" garage and not a stage piece so I know you'll need one of these anyway.

Grinding will leave a smooth but obvious different finish.
Cutting "slots" will work but can get filled with stuff.

If your happy with the slab as it sits ,minus the present concern, I'd leave it be and use a squeegee.

My thought's anyway.
Nice build BTW.